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MWL#182: Explain running statements

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- Merge with 5.3-main
This commit is contained in:
Sergey Petrunya
2011-10-27 21:41:19 +04:00
parent 08e9e6a790 ba09d25abc
commit 286a751490
25 changed files with 1365 additions and 126 deletions
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91
sql/sql_show.cc
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@@ -2027,6 +2027,97 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose)
DBUG_VOID_RETURN;
}
/*
SHOW EXPLAIN FOR command handler
@param thd Current thread's thd
@param thread_id Thread whose explain we need
@notes
- Attempt to do "SHOW EXPLAIN FOR <myself>" will properly produce "target not
running EXPLAINable command".
- todo: check how all this can/will work when using thread pools
*/
void mysqld_show_explain(THD *thd, ulong thread_id)
{
THD *tmp;
Protocol *protocol= thd->protocol;
List<Item> field_list;
DBUG_ENTER("mysqld_show_explain");
thd->make_explain_field_list(field_list);
if (protocol->send_fields(&field_list, Protocol::SEND_NUM_ROWS |
Protocol::SEND_EOF))
DBUG_VOID_RETURN;
/*
Find the thread we need EXPLAIN for. Thread search code was copied from
kill_one_thread()
*/
VOID(pthread_mutex_lock(&LOCK_thread_count)); // For unlink from list
I_List_iterator<THD> it(threads);
while ((tmp=it++))
{
if (tmp->command == COM_DAEMON)
continue;
if (tmp->thread_id == thread_id)
{
pthread_mutex_lock(&tmp->LOCK_thd_data); // Lock from delete
break;
}
}
VOID(pthread_mutex_unlock(&LOCK_thread_count));
if (tmp)
{
bool bres;
/*
Ok we've found the thread of interest and it won't go away because
we're holding its LOCK_thd data.
Post it an EXPLAIN request.
todo: where to get timeout from?
*/
bool timed_out;
int timeout_sec= 30;
Show_explain_request explain_req;
select_result_explain_buffer *explain_buf;
explain_buf= new select_result_explain_buffer;
explain_buf->thd=thd;
explain_buf->protocol= thd->protocol;
explain_req.explain_buf= explain_buf;
explain_req.target_thd= tmp;
explain_req.request_thd= thd;
bres= tmp->apc_target.make_apc_call(Show_explain_request::get_explain_data,
(void*)&explain_req,
timeout_sec, &timed_out);
if (bres)
{
/* TODO not enabled or time out */
my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0),
"SHOW EXPLAIN",
"Target is not running EXPLAINable command");
}
pthread_mutex_unlock(&tmp->LOCK_thd_data);
if (!bres)
{
explain_buf->flush_data();
my_eof(thd);
}
}
else
{
my_error(ER_NO_SUCH_THREAD, MYF(0), thread_id);
}
DBUG_VOID_RETURN;
}
int fill_schema_processlist(THD* thd, TABLE_LIST* tables, COND* cond)
{
TABLE *table= tables->table;